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根据电动振动台的工作原理,详细分析电动振动台磁路结构及漏磁场的来源,通过进行测量分析,并提出一种有效的漏磁场屏蔽措施。 相似文献
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硅橡胶电缆材料真空烘烤除气参数实验分析方法 总被引:1,自引:0,他引:1
目的在于通过硅橡胶电缆护套材料真空出气性能研究,分析材料真空烘烤除气的参数。方法是依据真空中材料出气性能测试标准,测试电缆材料使用温度范围内,不同温度条件下材料的质量损失(TML)、收集的可凝挥发物量(CVCM),分析材料出气参数的变化。结果硅橡胶电缆材料出气温度85℃时,CVCM量值与75℃时基本相同,出气温度95℃时,CVCM量值是85℃时的4倍,且收集到的物质组分也明显增加;出气温度85℃条件下,24小时后材料的质量损失约占总质量损失的94%。结论通过材料出气性能实验方法,有效获得了硅橡胶电缆材料真空烘烤除气参数,体电阻率测试结果检验了真空烘烤除气参数的合理性。 相似文献
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通过研究不同尺寸及分布的银粉对涂层表面电阻的影响,确定了导电屏蔽涂料最佳配方,制备了一种高导电、耐腐蚀涂层。采用SEM、EDS、四探针电阻测试仪等分析涂层在空气、水、盐水、中性盐雾、酸性盐雾中表面形貌及性能变化,从而揭示涂层腐蚀行为。结果表明:经历500 h试验后,涂层在空气中几乎没有发生变化,但是在含水等电解质的环境中腐蚀迅速,并且腐蚀速率具有纯水<水汽<盐水<中性盐雾<酸性盐雾的特征。腐蚀的主要原因是由于基材Al与涂层形成了电偶腐蚀,腐蚀初期表现为起泡,随着腐蚀的加剧,涂层表面布满白色、黄色、褐色的疏松腐蚀产物且漆膜出现脱落,当腐蚀进一步加剧扩大,疏松产物转变为较为致密的产物附着于涂层表面,此外,涂层导电性能会随着腐蚀程度的变化出现不同等级的下降。 相似文献
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As a policy instrument for sustainable development, nationwide circular economy (CE) mode has been implemented for 7 years by the Chinese government, to overcome the dilemma among economic depression, energy shortage and environmental pollution. Unfortunately, few literatures contribute to checking the efficiency of regional CE and exploring the potential reasons in China, which will be practically helpful in guiding China's future development and providing reference for other developing countries that will adopt CE mode. Therefore, this paper puts forward the method of super-efficiency DEA window analysis to dynamically evaluate CE efficiency of 30 regions in China covering the period of 2005–2010. In line with the features of CE, the specific efficiency of three sub-systems, namely resource saving and pollutant reducing (RSPR) sub-system, waste reusing and resource recycling (WRRR) sub-system and pollution controlling and waste disposing (PCWD) sub-system, was assessed and compared regarding time series trend and spatial distribution, based on which, the comprehensive CE efficiency was totally ranked. The results show that, on the one hand, during the period of 2005–2010, Chinese CE efficiency slightly increased, implying a significant policy effect of CE; on the other hand, the efficiency of different sub-systems varies, with RSPR sub-system the lowest, and WRRR and PCWD sub-systems relatively higher. In terms of regional distribution, the efficiency of RSPR sub-system in the east area dominates during the whole period. However, for the other two sub-systems, from 2005 to 2007, the efficiency scores of the east fluctuate, then after 2007, the east area became more efficient than the central and the west areas. Throughout the study period, the RSPR sub-system in the central area stably maintains low efficiency, and so does the WRRR sub-system in the west area. The difference in regional efficiency of three sub-systems reflects the difficulty of carrying out CE policy in China comprehensively, which means that, promoting the adaptability of regional policy for local government and enhancing the coordination among various policies for China's central government are the key concerns for realizing sustainable development. 相似文献
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90Sr、137Cs在某种包气带土壤中的迁移研究 总被引:4,自引:0,他引:4
本文叙述了放射性废物中具有代表性的裂变核素^90Sr、^137Cs在某种包气带土壤中的迁移情况研究。使用小型土柱的氚水淋洗实验研究土壤水力学性质,最后进行大型土柱实验研究核素在该包气带土壤中的迁移,并对实验情况进行了数学模拟。用该土壤原状土进行小型土柱的氚水淋洗试验,测得了土壤的水力弥散度为0.32cm,土壤有效孔隙度为0.35。经过290天的大型柱迁移试验表明,土壤对^90Sr的阻滞系数为220.4,在模拟实际降雨量的情况下,^90Sr的平均迁移速度为0.63cm/y,^137Cs在大型柱试验中没有明显迁移。数值模拟^90Sr、^137Cs迁移,得出经过上述大型柱试验相同的条件下,^90Sr、^137Cs迁移的峰位置基本和大型柱试验结果相同。 相似文献
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Barry D. Solomon 《Environmental management》1998,22(1):9-17
Dendroica kirtlandii ). This particular recovery program actually began before passage of the federal ESA, when biologists alerted the Michigan
Department of Natural Resources of the perilously low population of this bird, which only breeds under jack pine (Pinus banksiana) trees in Michigan. By the time an ESA Recovery Team was formed for this bird in 1975 (the first such team created under
the ESA), a legacy of consensus and interagency cooperation was well established. This has led to successful efforts at habitat
management and control of its nest parasite, the brown-headed cowbird (Molothrus ater). While the Kirtland's warbler is not yet recovered, its population is near an all-time high, and its recovery is possible
within the next decade. When (and if) this happens, it will be clearly attributable to this successful model of federalism
for natural resources management. 相似文献
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各级政府贯彻落实绿色发展的理念,实现经济增长与环境保护的共赢,才能真正实现"绿水青山就是金山银山"。在经济"新常态"背景下,防治环境污染是个复杂而系统性的工程,需要进行经济追因与综合治理,其中,制定实施有效的环境政策工具尤为关键。本文把微观经济学中的双寡头产量竞争模型作为基准模型拓展用于环境经济分析,并把环境税、环境规制、排污权交易这三类主要环境工具对企业生产决策的影响纳入基准模型,旨在对比研究不完全竞争行业中环境工具的有效性问题。结果表明:主要基于市场机制的环境经济政策比行政色彩浓厚的环境规制更有效率。提高环境税率或排污权价格均能显著削减行业污染物排放量,如果环境税率恰好等于排污权价格,则环境税与排污权交易这两类环境工具的效力相等。这对进一步建立和完善我国尚处于探索或初始实施阶段的环境工具,促进石化、电力、钢铁等不完全竞争行业的主要污染物减排,具有一定参考价值和借鉴意义。 相似文献
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含丰富藻类的河流由于藻类的光合作用与呼吸作用导致水中的溶解氧变化十分复杂且昼夜的变幅很大。使生化需氧量BOD_5的模拟所需采用的BOD_5—DO耦合模型的求解十分困难。本文根据在绵远河与石亭江的实际研究中采用了罗宾斯模型并作了合理的简化。利用藻类在夜间只有呼吸作用的特点进行溶解氧平衡计算以确定模型参数。在水质模拟中对模拟值与实测值作了比较,可看出模拟精度较好,因此本方法是适用和可取的。 相似文献
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通过工艺的对比试验,指出化学生物絮凝工艺去除效果要优于化学絮凝工艺,当投加相同量的絮凝剂和混凝剂时,前者比后者的去除效率提高了20%以上。同时通过测定耗氧速率证实化学生物絮凝系统内存在明显的生物作用。 相似文献